A novel AhR ligand, 2AI, protects the retina from environmental stress

Sci Rep. 2016 Jul 1:6:29025. doi: 10.1038/srep29025.

Abstract

Various retinal degenerative diseases including dry and neovascular age-related macular degeneration (AMD), retinitis pigmentosa, and diabetic retinopathy are associated with the degeneration of the retinal pigmented epithelial (RPE) layer of the retina. This consequently results in the death of rod and cone photoreceptors that they support, structurally and functionally leading to legal or complete blindness. Therefore, developing therapeutic strategies to preserve cellular homeostasis in the RPE would be a favorable asset in the clinic. The aryl hydrocarbon receptor (AhR) is a conserved, environmental ligand-dependent, per ARNT-sim (PAS) domain containing bHLH transcription factor that mediates adaptive response to stress via its downstream transcriptional targets. Using in silico, in vitro and in vivo assays, we identified 2,2'-aminophenyl indole (2AI) as a potent synthetic ligand of AhR that protects RPE cells in vitro from lipid peroxidation cytotoxicity mediated by 4-hydroxynonenal (4HNE) as well as the retina in vivo from light-damage. Additionally, metabolic characterization of this molecule by LC-MS suggests that 2AI alters the lipid metabolism of RPE cells, enhancing the intracellular levels of palmitoleic acid. Finally, we show that, as a downstream effector of 2AI-mediated AhR activation, palmitoleic acid protects RPE cells from 4HNE-mediated stress, and light mediated retinal degeneration in mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / toxicity
  • Animals
  • Apoptosis / drug effects
  • Cell Line
  • Fatty Acids, Unsaturated / metabolism
  • Humans
  • Indoles / chemistry
  • Indoles / pharmacology*
  • Ligands
  • Light
  • Lipid Peroxidation / drug effects
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Polychlorinated Dibenzodioxins / chemistry
  • Polychlorinated Dibenzodioxins / toxicity
  • Protective Agents / chemistry
  • Protective Agents / pharmacology*
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Reactive Oxygen Species / metabolism
  • Receptors, Aryl Hydrocarbon / antagonists & inhibitors
  • Receptors, Aryl Hydrocarbon / genetics
  • Receptors, Aryl Hydrocarbon / metabolism*
  • Retina / drug effects*
  • Retina / metabolism
  • Retina / pathology
  • Retina / radiation effects
  • Retinal Pigment Epithelium / cytology
  • Retinal Pigment Epithelium / drug effects
  • Retinal Pigment Epithelium / metabolism
  • Signal Transduction / drug effects

Substances

  • Aldehydes
  • Fatty Acids, Unsaturated
  • Indoles
  • Ligands
  • Polychlorinated Dibenzodioxins
  • Protective Agents
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Receptors, Aryl Hydrocarbon
  • 4-hydroxy-2-nonenal